Ok this is where my inexperience shows. I think (but don't know) that the larger creature is a flatworm. I spent a lot of time on the web trying to track it down without finding a exact match - flatworm is the closest I got to it. I cannot see any evidence of eyes even in the full size 3264x2448 images and even though I watched it for at least 30 minutes after I had taken these photos - I still couldn't spot any eyes.
*UPDATE* Bernhard has identified the larger creature as the ciliate Loxophyllum meleagris.
The photos were taken into a water droplet without a coverslip. I was just checking to see if there was anything interesting in the droplet before putting on the coverslip when I spotted this creature making a move on the ciliate - so I had no time to do anything other than take the photos. I took about 30 in this series just seconds apart - no time to use the 12 second self-timer (my usual method).
There was a very thin film on the surface of the dome-shaped droplet (which is why the field looks so messy) and Loxophyllum meleagris was near the surface. The dark blobs are ciliates swimming deeper down in the droplet.
I was particularly impressed by the way the creature used its tail to push the ciliate into its mouth/stomach.
[DONE] If you can identify the players in this little drama do please let me know.
The 6 images are in sequence (there are only three .jpg files I promise

Bruce


